4142 H.T. Tool Steel

Chemical Analysis:
Carbon .38/.46
Manganese .70/1.70.
Phosphorus .035 Max.
Sulfur .040 Max.
Silicon .15/.35
Chromium .75/1.20
Vanadium .10 Max.
Tungsten -------
Molybdenum .15/.25
Cobalt -------
Tempering Temp. º(F): Hardness Rc
As-quenched 60.1
400 57.8
500 53.4
600 49.5
700 46.1
800 42.9
900 38.8
1000 34.1
1100 31.1
1200 27.7
1300 23.5


Brake die, support tooling, die holders, short run stamping and bending dies.


Heat slowly and uniformly to a temperature of from 1750° F to 1850° F.  Cool slowly from the forging or rolling temperature.


Heat slowly to 1500° F, and hold for 1/2 hour per inch of thickness.  Furnace cool at 20° F per hour to 1230° F; air cool to room temperature.   Expected Brinell hardness 197 max.


4142 material is prehardened from the mill to a hardness of BHN 270/320 in thicknesses to 4" inclusive and BHN 260/310 in thicknesses over 4" to under 6" inclusive.  CAUTION: 4142 material must be annealed prior to rehardening treatment to obtain a higher hardness.  Heat treat the same as 4140.


No tempering is required, since the material is already prehardened at the mill.  If the material is rehardened to obtain a higher hardness, the above tempering table may be used as a guide.  Parts should be held a minimum of 1 hour per inch of thickness.  A single temper is sufficient.  However, since 1/2" dia. specimens were used for this test, it may be found that heavier sections are several points lower.